The Extension Site
is located at TKO Area 137 with a piggyback area occupying the southern slope
of the existing SENT Landfill and its infrastructure area and extends over the
boundary of the Clear Water Bay Country Park (CWBCP). Figure 3.1a shows the location
of the Extension Site.
The Extension Site
is surrounded by existing and future developments on the northern, southern and
western sides. To the north of the
Site is the existing SENT Landfill.
To the south and west of the Site is a reclaimed area currently used by
the Civil Engineering and Development Department (CEDD) for a fill bank operation. The
eastern side of the Site is bounded by the natural headland of the CWBCP. The sides of the natural headland
adjoining the Site are steep, undeveloped and support grassland or shrub
vegetation. This headland forms a
natural screen between the Extension and the largely undeveloped environments
of
The nearest
existing development to the Extension Site is the industrial development within
TKOIE located to the northwest and separated by
In the 1990s, the
SENT Landfill and the surrounding area were relatively remote and lightly
populated. In the intervening
years, there has been considerable development nearby. Further reclamation has occurred on the seaward
side of the SENT Landfill. This
reclamation is now occupied by the TKOIE and the TKO Area 137, where the
Extension Site will be located. The
majority of TKO Area 137 is currently occupied by the temporary public fill
bank. The fill bank is used for
storage of inert construction and demolition material, pending its beneficial
reuse in construction projects elsewhere.
The Extension Site
area within the CWBCP, designated in 1979, is undeveloped. Part of the natural coastline of the
CWBCP was lost due to the development of the SENT Landfill and the reclamation
of TKO Area 137.
The Extension is a
piggyback landfill, occupying the existing SENT Landfill infrastructure area,
15 ha of TKO Area 137 and approximately 5 ha of the CWBCP. A layout plan of the Extension is shown
in Figure 3.3a. The new infrastructure area will be
located to the south of the waste filling area. Figure 3.3b shows the layout of
the infrastructure area, which houses the landfill gas treatment facility and
leachate treatment plant, offices, maintenance workshops, etc.
The Extension covers an area of around 50 ha (including all site
infrastructure). Discounting the
void space required for miscellaneous engineering works and daily and
intermediate covers, the total net void capacity for waste is estimated to be
around 17 Mm3. The
lifespan of the Extension is estimated to be around 6 years, commencing
operation in 2013 ([1]).
The design of the
Extension comprises the following key components:
·
Landfill liner and capping;
·
Landfill gas management system;
·
Leachate management system;
·
Surface water management system;
·
Groundwater management system; and
·
Site infrastructure.
The design of
these components is described in the following sections.
The Extension will
be designed and constructed as a fully contained facility incorporating
multilayer composite liner systems covering the entire surface area of the
Extension Site where waste will be deposited. Four different liner systems will be
used for the different areas of the Extension Site, as follows:
·
Basal;
·
Rock slope;
·
Soil slope; and
·
Piggyback
Sections of the liner
systems are shown in Figure 3.3c. In general, the design of all liner
systems contains at least one impermeable layer, ie HDPE liner, a geocomposite
clay liner (GCL), a geotextile cushion, and leachate and groundwater drainage
layers.
After final levels
of waste are reached, a protective soil layer will be placed over the waste
before placing the final cap. The
final cap comprises non-woven geotextile, HDPE liner (impermeable layer), a
drainage layer and a soil layer.
The impermeable liner and cap will form a containment of void for waste
so as to ensure that the waste is completely separated from the surrounding
environment. Hence, this
containment system will ensure minimal runoff and groundwater entering the
waste and prevent off-site migration of leachate and landfill gas.
Three types of
collectors are proposed to be included to provide effective collection of landfill
gas at the Extension as soon as possible:
·
Horizontal collectors above the leachate drainage
layer – these have been allowed for at approximately 100m intervals above the
basal liner system;
·
Horizontal collectors in the waste mass – these have
been allowed for at approximately 75m centres; and
·
Vertical drilled wells – at 40m centres on the
perimeter of the waste boundary and 80m centres within the body of the waste
nass.
The locations of
these collectors are shown in Figure 3.3d. Together with the impermeable liner as
part of the intermediate cover system, and the final capping system, these
types of collector effectively minimise landfill gas emissions from the
Extension at any time during the operation.
To avoid damaging
the liner system of the Extension, modifications to the landfill gas collection
wells at the southern waste slope of the existing SENT Landfill will be
required. The modification work
will include removal of well pipes, placement of a concrete cap over the top of
the affected wells and installing a short length of pipe to connect the
affected wells to the existing gas collection system of the SENT Landfill (see Figure
3.3e). If the existing
landfill gas collection wells are damaged beyond economical repair and rendered
useless or it is considered that there is a need to have greater collection
ability during the construction of the Extension, new wells can be drilled to
enhance gas collection.
As part of the
liner design, a landfill gas drainage layer will be sandwiched between the SENT
Landfill cap and the Extension liner (see Figure 3.3f). This gas drainage layer comprises a
layer of granular fill over the landfill surface and to collect gas emanating
from the surface should leakage in the capping system and around the damaged
gas wells occur. It also serves a
secondary function to provide a mean of collection which may be beneficial
after a period, when settlement is or has occurred, and the existing and
interim gas collection system and/or cap has suffered damage.
Interim pipework
will be required to connect the various collector types in both the Extension
and the existing SENT Landfill. The
pipework will be laid using either welded HDPE pipes laid over the surface, or
a system of reasonable flexible convoluted polypropylene pipe with suitable
robust connection methods. The
interim pipework can be laid to connect the landfill gas treatment facility at
the infrastructure area or to localised temporary gas flares.
Permanent pipework
will be installed to eventually connect all gas collectors and allow the gas
extracted to be delivered to the landfill gas treatment facility. It will be laid over the surface,
provided that the polymer used contains sufficient UV inhibitors to prevent
degradation occurring.
Alternatively, the pipework will be buried within the landfill cap.
The landfill gas
collected from the existing SENT Landfill will be delivered to the landfill gas
utilisation plant proposed by GVL and the remaining gas will be delivered to the
landfill gas treatment facility located at the new infrastructure area. The landfill gas collected from the
Extension will be transferred to the landfill gas treatment facility located in
the infrastructure area.
The landfill gas
treatment facility will be located in the infrastructure area and will comprise
the following key components:
·
Condensate knockout pot to remove moisture droplets;
·
Gas boosters to provide suction to the well field and
pressure to downstream facilities;
·
Enclosed flares to efficiently destroy the methane and
trace components;
·
A control system to ensure safe initiation of the
flare burn and subsequent operation; and
·
Connections to permit an off-take for utilization of
the landfill gas.
The predicted gas yield indicates that a peak combined gas flow from
both the Extension and the existing SENT Landfill of approximately 16,600 m3
hr-1 is expected in year 2020, whilst the flow is anticipated
to be over 10,000 m3hr-1 over a twenty year period,
between 2008 and 2028. The design
will include two identical enclosed flares with a capacity of 10,000 m3 hr-1
each, to provide a maximum handling capacity of 20,000 m3 hr-1.
Landfill gas is flammable, which has value
as a renewable fuel and has utilised as such around the world in many
applications. The
potential utilisation options which may be considered for the landfill gas
collected from the Extension include:
·
On site utilisation in the leachate
treatment plant;
·
On-site utilisation for site power
requirements;
·
Delivery to the proposed landfill gas
utilisation plant at the existing SENT Landfill;
·
On-site Combined Heat and Power (CHP);
·
Dedicated use in the adjacent industrial
area. Uses include direct firing in boilers for process heat, or in an
absorption chiller to provide for air conditioning or CHP schemes; and
·
Power generation for export to the CLP
grid.
The precise type of utilisation will be
determined during the detailed design stage by the Extension Contractor. For the purpose of the assessment, it is
assumed that landfill gas will be used to fuel the LTP while the remaining gas
will be flared.
With the proposed
design of the liner and capping systems, water ingress into the Extension will
be minimized and off-site migration of leachate will be negligible. Leachate will be contained and collected
via the collection system to the LTP in the new infrastructure area. The main features of the leachate
management system are:
·
Leachate collection system comprising aggregate and
geosynthetic drainage layers;
·
Leachate extraction system comprising HDPE sideslope
risers and collection sumps; and
·
The LTP.
Location of the
main features of the leachate management system is shown in Figure
3.3g.
The leachate collection layer is designed to collect and
drain leachate which percolates downwards from the waste. The layer, comprising aggregate (a
minimum depth of 300mm) in the basal liner or geosynthetic drainage layer (in
the slope and piggyback liners) will be placed on top of the impermeable liner
with a layer of cushion (eg geotextile) between the two. Drainage pipework will be installed
within the leachate collection layer in the basal liner. At the piggyback and side slope area,
leachate will be collected at the geosynthetic drainage layer and flow by
gravity to the basal liner where leachate will be collected by the
pipwork. The pipework will be
manufactured from either HDPE, u-PVC or polypropylene, and will be perforated
(with slots or holes) except for the lower 120o of the pipe
cross-section, which will be solid to allow for flow of leachate. The leachate drainage pipework will be
designed such that the maximum head of leachate above the basal lining system
does not exceed 1m. The maximum
pipe spacing will be 50m, and the gradient should be at least 1(v) : 50(h). The pipework will collect leachate from
the waste and drain it to the collection sumps.
Leachate
will be extracted from the landfill via four collection sumps around the
western and southern perimeter of the Extension Site (see Figure 3.3g).
The
leachate collection sumps will be constructed of pre-cast concrete and will be
equipped with submersible pumps to enable leachate to be pumped from the base
of the landfill to the leachate collection main, which will transfer leachate
to the LTP in the new infrastructure area.
The
leachate collection sumps will be accessed by HDPE upslope risers along the toe
bund of the Extension, and therefore will not be prone to damage due to
movements of the waste mass.
The process flow
diagram of the proposed leachate treatment process is shown in Figure
3.3h. All processing tanks,
except the SBR tanks, will be covered.
The
predicted average daily leachate flow from the Extension during its period of
operation is 332 m3 d-1. However, the daily flow rate will vary
according to seasonal rainfall. The
predicted average daily flow from the existing SENT Landfill following
restoration is 23 m3 d-1.
The proposed leachate treatment option is to provide an LTP
with maximum design flow rate of 1,500 m3 d-1, coupled
with a buffer storage capacity of 22,000 m3. This capacity will be able to cope with
the anticipated peak leachate treatment requirement during the last year
operation of the existing SENT Landfill when the existing Bioplant will be
demolished, and subsequently during the Extension operation. Following full restoration of the
existing SENT Landfill, the buffer storage capacity could be reduced, subject
to further review, as the leachate generation from the Extension is
smaller. Table 3.3a summarises the design leachate flow and quality of the
LTP.
Table
3.3a Summary
of Design Leachate Flow and Quality Used in Plant Sizing
|
Design
Flow Rate |
|
1,500 |
|
m3d-1 |
|
Design
effluent limits |
|
|
|
|
|
Total
inorganic nitrogen (TIN) |
|
100 |
|
mgL-1 |
|
Total
nitrogen (TN) |
|
200 |
|
mgL-1 |
|
COD |
|
2,000 |
|
mgL-1 |
|
Design
Raw Leachate Quality |
Mean |
Max |
Min |
|
|
Influent NH4-N |
2,500 |
4,500 |
1,500 |
mgL-1 |
|
Influent COD |
3,000 |
4,500 |
2,000 |
mgL-1 |
|
Hard COD |
1,000 |
1,500 |
650 |
mgL-1 |
|
Hard TKN |
75 |
125 |
40 |
mgL-1 |
From the buffer storage tanks, leachate will be pumped to the metal precipitation
system and then to ammonia stripping plant which consisting of two stripping
towers, two thermal oxidizer towers (one operating and one on standby), heat
exchangers and ancillary equipment.
The two ammonia stripping towers, each with a capacity of 750 m3 d-1
can operate alternately to allow for regular maintenance. The stripping process would
be operated to remove approximately 92 to 98% of the ammonia, leaving
approximately 100 to 200 mg L-1 of ammonical nitrogen (NH4-N)
to be removed biologically together with the degradable chemical oxygen demand
(COD). The ammonia-laden air then
passes to the thermal oxidizer where the ammonia will be oxidized to nitrogen
gas prior to discharge to atmosphere.
Stripped
effluent will be stored in a holding tank from where it will be fed to the
Sequential Batch Reactor (SBR) tanks.
The
SBRs will operate on a 24-hour cycle with denitrification. From the SBRs, treated leachate is
decanted, after a settling period, into the final effluent holding tank. This allows continuous discharge of the
treated effluent to the receiving foul sewer. The Sewerage Impact Assessment has
confirmed that the existing sewage infrastructure is adequate for the
predicted flows.
The LTP will be commissioned during the last year of operation at the
SENT Landfill and will replace the existing Bioplant of the SENT Landfill. The LTP is capable of treating leachate
to comply with the discharge standard stipulated in the existing discharge license
of the SENT Landfill. Following
closure and restoration of the existing SENT Landfill, leachate generation at
the existing SENT Landfill will be reduced significantly. It is estimated that the averaged
combined leachate flow from the restored SENT Landfill and the operating
Extension will be around 355 m3 d-1 while the peak
treated effluent flow will be limited to 1,000 m3 d-1. The LTP is capable of
treating leachate to comply with discharge standards stipulated in EPD’s Technical Memorandum Standards for Effluents
Discharged into Drainage and Sewage Systems, Inland and Coastal Waters.
The surface water
management system for the Extension is designed to minimise surface water
entering the Extension Site from the upgradient area of CWBCP and the restored
slope of the existing SENT Landfill.
It also controls contaminated runoff from the Extension Site entering
the surrounding area. Key features
of the surface water management system include:
·
Permanent perimeter cut-off channel and drainage
tunnels;
·
Temporary cut-off channels; and
·
Sediment traps and oil separator.
The location of
these features is shown in Figure 3.3i.
A permanent cut-off
channel will be constructed along the waste boundary of the Extension and will
connect with the drainage features that are incorporated into the SENT Landfill
restoration design. The southern part of this cut-off channel
will drain by gravity to the south-eastern corner of the Extension. The northern part of this cut-off
channel falls to the north, to a low point near the south-eastern corner of the
existing SENT Landfill, where it will meet up with the existing cut-off channel
for the existing SENT Landfill.
At present, the existing SENT Landfill
cut-off channel traverses the eastern edge of the landfill, and then turns to
the west, towards the existing SENT Landfill infrastructure area. As part of the Extension development,
this portion of the channel will be covered by waste. The design of the surface water
management system has therefore included the construction of a twin drainage
tunnel (2,000mm diameter) to drain surface water collected at the low point
near the south-eastern corner of the existing SENT Landfill to TKO Area
137. The outfall of the twin
drainage tunnels will join the perimeter cut-off channel at the eastern
boundary of the Extension in TKO Area 137.
Following completion of the Extension, an
additional channel will be constructed around the eastern flank of the
Extension and then to the west, to convey flows directly to the western
boundary of the Extension Site avoiding the low point to the east.
Prior to completion of the Extension,
temporary collection and pumping of surface water (at low points) will be
required as part of the surface water management plan, to avoid any discharge
of stormwater eastwards into
Run-off that has
been in contact with waste will be treated as leachate and collected for
treatment at the LTP.
Rain falling onto the restored slopes of
the Extension will be collected by surface water channels on the slopes, and
drained to the perimeter of the Extension Site.
Rain falling onto areas of active tipping and
daily cover areas will infiltrate into the waste and be collected by the
leachate collection system, for treatment prior to discharge into the foul
sewer.
A series of temporary cut-off channels
will be constructed on the side slopes and on the southern waste slopes of the
existing SENT Landfill that lie within the Extension. These channels will intercept rain
falling on areas above the active tipping face, and divert it to the perimeter
cut-off channels.
Within each development phase, areas
outside the active tipping face will be covered with intermediate cover. In order to minimise odour emission,
leachate generation and to control contamination of surface water runoff, the
intermediate cover will include an impermeable liner. Temporary surface water management will
be provided in order to collect rain falling onto areas of intermediate cover,
and divert the clean runoff to the perimeter cut-off channels.
All surface water drainage channels that
discharge either directly or indirectly to surface watercourses or to the sea
will be provided with sediment traps, stilling basins and oil separators to
control suspended solid concentrations and oil in the surface water discharged
from the Extension Site.
Groundwater will be managed to prevent a
hydrostatic build-up of water below the base liner and to prevent contamination
by leachate. The basal liner has
been designed to contain two impermeable layers to avoid leachate migrating out
of the lining system. The design of
the leachate collection system will also minimise the leachate head and thus
minimise the driving force of leachate migration through any holes in the base
and sideslope liner system. A
geocomposite drainage layer below the base liner (see Figure 3.3c) will
collect and transport groundwater away from the liner. The base of the Extension has been kept
above the groundwater level, in order to minimise difficulties during
construction, and minimise the consequences of any leakage from the lining
system.
The
groundwater collection layer on the side slopes of the Extension will be
connected to groundwater diversion pipe trenches, and groundwater flows will be
diverted to a series of groundwater collection sumps along the western boundary
of the Extension adjacent to the leachate sumps before discharge off-site (see Figure
3.3j). The design has
allowed for the provision of a submersible pump in the sump for pumping to the
leachate collections sumps (adjacent) in the event of contamination being
detected.
The new
infrastructure area is located south of the waste filling area. This area is occupied by offices,
maintenance workshops, landfill gas treatment facility and the LTP, as shown in
Figure
3.3b. A loop road system is
designed to provide access to all tanks and equipment within the infrastructure
area. A 5m wide landscape planting
strip has been allowed along the boundary to screen the access road and the
infrastructure area.
Other site
infrastructure includes the weighbridge and vehicle washing facility, located
to the north of the new infrastructure area. The weighbridges will be enclosed and
will be maintained at a slight negative pressure. Air extracted from the enclosed area
will pass through the air scrubbing system prior to discharge to the
atmosphere.
The vehicle
washing facility will be located just before the out-weighbridge. The water spray at the facility will
ensure that the outside of the whole vehicle to be washed so as to minimize
potential odour impacts from the RCVs leaving the Extension Site. The wash water will be drained to the
LTP for treatment.
The key tasks of
the Extension development are shown in Figure 3.4a. Construction works will commence
two years prior to commencement of waste filling. The Extension will be developed and
operated under six phases, each will last for about one year. Upon the completion of each phase, the
areas that reached the final profile will be restored immediately.
Construction works
will commence in early 2011, two years before the Extension starts
operation. During the first year of
construction, works including site formation and construction of superstructure
will be carried out in the new infrastructure area. Pipes will be constructed to transfer
the leachate and landfill gas collected from the existing SENT Landfill to the
treatment facilities at the new infrastructure area. Waste reception facilities, including
the site access road and weighbridges and monitoring wells will also be
constructed.
Formation of side slopes on the eastern side of the Extension will begin
in the third quarter of 2011. The
formation of side slopes will require blasting of the rock slopes. The total volume of rock to be excavated
for the Extension is around 320,000 m3. With the assumption that there will be
one blast per day and a volume of 3,000 m3 per blast, the total
blasting period would be around 107 days. The quantity of explosive used and
the dimensions and spacings of shotholes will be carefully designed to minimize
air overpressure, flyrock generation and ground-borne vibration. To minimize environmental impacts and
ensure safe operation, loose material and stones in the Site will be removed
prior to the blast operation. The
area within 30m from the blasting area will be wetted prior to blasting to
minimize dust generation. During
blasting, blast nets, screens and other protective covers will be used to
prevent the projection of flying fragments and other material resulting from
blasting.
The rock obtained
from blasting will be crushed on-site for reuse as leachate stone and
subsequent site formation and engineering works.
The construction
of the surface cut off drain and the 2,000mm twin drainage tunnels will
commence in the third quarter of 2011 and will last for about 6 months. The tunnels will be constructed using
micro-tunnelling techniques (using a tunnel boring machine (TBM)). The tunnel will be constructed from the
lower end, ie at TKO Area 137.
In the second
year, plant and equipment in the new infrastructure area will be commissioned,
followed by demolition of the existing infrastructure at the SENT
Landfill. This arrangement will
ensure that treatment of leachate and landfill gas from the existing SENT
Landfill is not interrupted.
The base grades of
the waste filling area will be formed, followed by laying of base liner and the
groundwater and leachate collection system. The formation of side slopes with
blasting will continue throughout the second year and be completed by 2012.
The waste filling
area will be ready for tipping operations in 2013.
The Extension will
be developed in six phases (see Figures 3.6a to 3.6k). Towards the end of each phase, liner
will be installed on the side slope for the next phase.
Based on the waste
arisings forecast, the Extension will receive on average around 8,600 tonnes
per day throughout its operational life time, generating around 1,500 vehicle
per day ([2]). It is anticipated that the Sludge
Treatment Facilities (STF) will commence operation in 2012, before the
commissioning of the Extension. The
incineration ash generated by the Integrated Waste Management Facilities (IWMF)
planned to be in operation by 2014 will also be disposed of at the
Extension. Hence, the type of waste
to be received by the Extension will include MSW, construction waste and
special waste (without sludge from the sewage treatment facilities ([3])
but
including the residues from the STF and IWMF).
Similar to the
existing practice, the Extension will be receiving waste from 8:00am till
11:00pm. Preparation of the daily
tipping face will start before 8:00am.
The preparation work includes mobilizing equipment to the tipping face
and removal of cover soil. The
special waste trench will be constructed after 8:00 am.
When a waste collection vehicle arrives at the site, it will go through
the in-weighbridge and then heading to the designated tipping face. The size of the active tipping face will
be around 1,200 m2. The
waste collection vehicle will unload the waste in the designated areas,
depending on the type of waste it is carrying. In general, MSW and the non-inert waste
are unloaded in the “wet waste” tipping area, the inert waste and construction
waste are unloaded in the “dry waste” tipping area and selected special waste ([4])
is
unloaded in the special waste trench, approximately 15 m2 in
size. Waste unloaded in the “wet
waste” tipping area will be immediately covered by the construction waste from
the “dry waste” tipping area. Waste
will then be compacted by landfill compactors and dozers. When the waste collection vehicle leaves
the tipping area, it will go through the vehicle wash facility and the
out-weighbridge before leaving the Extension Site.
Towards the end of
each working day the whole tipping face will be covered with 300mm of soil and
compacted. The special waste trench
will be opened from 9:00am to 6:00pm and will be covered with soil immediately
after closure.
To control odour
emission and reduce leachate generation in areas not actively used for tipping
(ie the intermediate covered area), an impermeable liner will be placed on top
of the 600mm thick cover soil ([5]). When the area is to be used for tipping,
the impermeable liner and the cover soil will be removed.
It is expected
that the landfill operation will last for about six years. The Extension will be operated to comply
with international best practice for landfill operation.
Areas filled to
final grades will be restored as soon as possible. Restoration will be carried out in
stages as phases are progressively filled with waste. After final levels are reached within a
given phase, a 300mm protective soil layer will be placed over the waste. The final cap, comprising a non-woven
geotextile, a HDPE geomembrane, a high permeability geocomposite drainage layer
and a 1,500mm fill layer, will then be placed (see Figure 3.3c).
The first 1,200mm
of fill directly above the drainage layer will be compacted to reduce surface
water infiltration. The thickness
of the fill layer will be increased in some planting areas to provide depth
sufficient to prevent damage to the liner from vegetation rooting. After placement of the final cover
system, the areas will be landscaped.
Vertical landfill
gas extraction wells will be drilled during restoration. The restoration work will also include
the construction of permanent surface water drains.
Upon completion of
final filling and site restoration, the period of aftercare will begin and last
for 30 years. During this period,
by-products from waste disposal will continue to be generated including
leachate and landfill gas. The
established leachate and landfill gas management control and treatment
facilities will continue to operate throughout the aftercare period.
Regular site
maintenance will be required during the aftercare period to keep the
incorporated systems functioning as designed. Site monitoring during the aftercare
period will continue in accordance with the monitoring plan, but may be
decreased if warranted and approved by the EPD.
During the
aftercare period, afteruse(s) could be developed on the restored landfill for
beneficial uses. However, the
definition of the afteruse development is outside the scope of the current
assessment and the Extension contract.
A separate feasibility study and environmental impact assessment (if
required) will be carried out for the development of the afteruse(s).
There will be an
overnight switch of tipping areas from the existing SENT Landfill to the new tipping
area at the Extension. During the
first quarter of the operation at the Extension, restoration at the last
filling area at the existing SENT Landfill will be undertaken. Based on the phasing plan from the
existing SENT Landfill operator, the last filling area will be located at the
northern end of the existing SENT Landfill, as shown in Figure 3.9a. Since the distance between the last
filling area at the SENT Landfill and the new active tipping face at the
Extension is over 1km, cumulative impacts are not anticipated.
The rest of the
area in TKO Area 137 is currently planned for Deep Water Front Industrial
uses. With reference to the
Engineering Feasibility Study of Development of TKO Area 137 (March 1993),
potential hazardous installation (PHI) may be developed in the area and hence
there is a worker density restriction imposed in TKO Area 137, although there
is no committed PHI development at presence. The risk assessment as part of that
Engineering Feasibility Study recommended a worker density of 30 persons/ha
within the Consultation Zone in Area 137.
As the worker density at the Extension during both construction and
operation phases will not exceed this recommendation, it is expected that risk
to the workers within the Extension Site due to the potential PHI development
is acceptable.
While the planning
of landuses within TKO Area 137 is still ongoing, a Construction and Demolition
Material Handling Facility is committed to be located at the TKO Area 137 (see Figure
3.9b). The Facility is
planned to start operation in phases in 2009. The capacity of the Facility is 20,000
tpd. The potential cumulative dust
impact is addressed in Section 4.
The programme of
developing other uses in TKO Area 137 is uncertain at the moment. Hence, cumulative impacts cannot be
assessed in this EIA. Nevertheless,
these uses have been considered as sensitive receivers, where appropriate, in
this EIA.
